Immunotherapy In Malignant Pleural Mesothelioma Research Articles

Pleural Effusion of Patients with Malignant Mesothelioma Induces Macrophage-Mediated T Cell Suppression

IntroductionClinical studies have demonstrated beneficial effects of immunotherapy in malignant pleural mesothelioma. The pleural cavity seems an attractive compartment to administer these types of therapies; however, local immunosuppressive mechanisms could hamper their efficacy. Macrophages are abundantly present within the mesothelioma microenvironment. This study investigates the influence of the macrophage phenotype, macrophages' capacity to inhibit local immune responses, and the decisive role of pleural effusion (PE) in this regard. MethodsWe cultured macrophages in the presence of PEs and investigated their phenotype. Macrophages and T cells were cocultured in the presence of PEs and tumor cell line supernatants. The levels of 11 cytokines and the prostanoid prostaglandin E2 were measured in PEs and supernatants. The presence and phenotype of macrophages and T cell subsets was measured in the PE of patients with mesothelioma. ResultsPE induced a tumor-promoting M2 phenotype in macrophages, which was confirmed by the suppressive activity of macrophages on T cell proliferation during coculture. Prostanoid prostaglandin E2 was identified as a potential inducer of the suppressive capacity of macrophages in PE. Macrophages isolated from PEs displayed an M2 phenotype and were negatively correlated with T cells in vivo. ConclusionsThe current study demonstrates that macrophages in PE can play a pivotal role in directly hampering the antitumor T cell immune response. This emphasizes the potential of macrophages as a therapeutic target in mesothelioma and indicates that the presence and phenotype of macrophages in PE should be taken into consideration in the application of (intrapleural) immunotherapies.

Abstract A075: Immunotherapy of malignant pleural mesothelioma using cMET specific T-cells

Abstract Background: Malignant pleural mesothelioma (MPM) is an incurable cancer predominantly induced by asbestos exposure. This aggressive tumour commonly presents at an advanced stage of disease. Although surgery, combination chemotherapy and radiotherapy may be used in disease management, median survival from diagnosis is less than 12 months. New therapeutic approaches are required to improve outcome in this disease. Chimeric antigen receptors (CAR) are fusion molecules that couple the HLA- independent binding of a selected cell surface target antigen to the delivery of a tailored T-cell activating signal. Using CAR technology, we aim to develop a novel immunotherapy for MPM that is both safe and effective. These molecules are delivered to patient T-cells using retroviral gene-transfer, thereby stably re-directing their specificity for antigen. The receptor tyrosine kinase MET is overexpressed in >80% of MPM patients making it an attractive candidate for CAR directed immunotherapy. Methods: Three second-generation cMet-targeted CARs (containing a fused CD28/CD3ζ endodomain) have been developed, distinguished by peptide-binding motifs. Functionality of MET-re targeted T-cells has been assessed by co-cultivation of genetically enhanced test and control T-cells with MPM cell lines that express MET at various levels. Results: Studies to date have shown that human T-cells engineered to express cMet CARs can destroy mesothelioma tumour cell monolayers, accompanied by T-cell proliferation and cytokine production. To further potentiate the activity of the cMet targeted CARs, a dual targeting approach to both cMet and the ErbB family is currently under evaluation. The second advantage of this approach is in diminishing the potential toxicity risks associate with “on target, off tumour” toxicity. An MPM xenograft model has been established utilising bioluminescence to further evaluate functionality and toxicity in vivo. Conclusions: These findings demonstrate proof of concept for the utility of CAR engineered T-cells to recognise and destroy cMet-expressing MPM tumour cells. We envisage that regional i.e. intrapleural delivery of human CAR positive T-cells could be used to maximise therapeutic index of this approach. Citation Format: Thivyan Thayaparan, Sjoukje J.C. van der Stegen, Ana C. Parente Pereira Puri, Roseanna Maria Petrovic, James Spicer, John Maher. Immunotherapy of malignant pleural mesothelioma using cMET specific T-cells. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr A075.

Abstract 2800: Immunotherapy of malignant pleural mesothelioma using MET specific t – cells

Abstract Background: Malignant pleural mesothelioma (MPM) is an incurable cancer predominantly induced by asbestos exposure. This aggressive tumor commonly presents at an advanced stage of disease. Although surgery, combination chemotherapy and radiotherapy may be used in disease management, median survival from diagnosis is less than 12 months. New therapeutic approaches are required to improve outcome in this disease. Chimeric antigen receptors (CAR) are fusion molecules that couple the HLA-independent binding of a selected cell surface target antigen to the delivery of a tailored T-cell activating signal. Using CAR technology, we aim to develop a novel immunotherapy for MPM that is both safe and effective. These molecules are delivered to patient T-cells using retroviral gene transfer, thereby stably re-directing their specificity for antigen. The receptor tyrosine kinase MET is overexpressed in >80% of MPM patients making it an attractive candidate for CAR directed immunotherapy. Methods: Three MET-targeted peptide-binding motifs have been incorporated into a second generation CAR framework containing a fused CD28/CD3ζ endodomain. Functional assessment of MET-targeted CARs has been assessed by co-cultivation of genetically enhanced test and control T-cells with MPM cell lines that express MET at various levels. Results: In preliminary studies we have shown that human T-cells engineered to express MET CARs can destroy mesothelioma tumor cell monolayers, accompanied by T-cell proliferation and cytokine production. Xenograft models are currently under development using bioluminescence to further evaluate functionality and toxicity in vivo. Conclusions: These findings demonstrate proof of concept for the utility of CAR engineered T-cells to recognise and destroy MET-expressing MPM tumor cells. We envisage that regional i.e. intrapleural delivery of human CAR positive T-cells could be used to maximise therapeutic index of this approach. Citation Format: Thivyan Thayaparan, Sjoukje v.d Stegen, Ana C. Parente Pereira, Roseanna Petrovic, James Spicer, John Maher. Immunotherapy of malignant pleural mesothelioma using MET specific t – cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2800. doi:10.1158/1538-7445.AM2014-2800

Overexpression and potential targeting of the oncofoetal antigen 5T4 in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is resistant to conventional treatments. Novel, targeted treatments are hampered by the relative lack of MPM-associated tumour antigens. The aim of this study was to evaluate the level of expression and the relevance of 5T4 as a tumour-associated antigen in MPM. 5T4 expression was assessed by Western blotting, flow cytometry, immuno-cytochemistry and -histochemistry in 11 mesothelioma cell lines, 21 tumour biopsies, and ex vivo tumour cells obtained from the pleural fluid (PF) of 10 patients. 5T4 antibody levels were also determined in the plasma of patients and healthy donors. The susceptibility of MPM cells to 5T4-specific T-cell-mediated killing was determined using an HLA-A2+, CD8+ T-cell line, developed against the 5T417–25 peptide. We report here that cell surface 5T4 expression was detected in all mesothelioma cell lines and PF cell samples. Mesothelin and CD200, a suggested mesothelioma marker, were co-expressed with 5T4 on tumour cells in PF. Immunohistochemistry confirmed overexpression of 5T4, similar to mesothelin, on tumour cells but not on reactive stroma in all tissue sections tested. Median 5T4 antibody levels were 46% higher in patient than in healthy donor plasma, indicating immune recognition. Importantly, 5T4-specific CD8+ T-cells were able to kill four out of six HLA-A2+ MPM cell lines but not an HLA-A2− cell line, demonstrating immune recognition of MPM-associated 5T4 antigen at the effector T-cell level. We conclude that 5T4 is a potential new antigen for targeted therapies such as immunotherapy in MPM, as it is overexpressed on mesothelioma cells and recognised by 5T4-specific cytotoxic T-cells. Our findings have been translated into a Phase II clinical trial applying 5T4-targeted therapies in MPM patients.

Abstract 4784: CD8+ tumor-infiltrating lymphocytes predict favorable prognosis in malignant pleural mesothelioma

Abstract Purpose: Defect in human leukocyte antigen (HLA) class I expression may provide tumor cell with a mechanism to escape immune recognition, while T-cell infiltration is associated with good prognosis in many cancers. However, little has been known about the role of HLA class I expression and tumor-infiltrating lymphocytes (TILs) in malignant pleural mesothelioma (MPM). In this study, we investigated the immune profile and conducted outcome analyses in MPM patients. Experimental Design: HLA class I expression and TILs (CD4+, CD8+, and NK cells) were detected by immunohistochemistry in a series of 44 MPM cases. To detect HLA class I expression, specimens were stained with the anti-pan HLA class I monoclonal antibody EMR8-5. Results: The expression of HLA class I was positive in 33 patients (75%) and heterogenous in 11 patients (25%). There was no case that showed negative HLA class I expression. The density of CD4+ and CD8+ TILs were strongly correlated (R = 0.76, p<0.001). High density of CD8+ TILs were significantly better prognostic factor for survival of patients with extrapleural pneumonectomy (p<0.05). Multivariate analysis revealed high density of CD8+ TILs to be an independent prognostic factor. Conclusion: The presence of intratumoral CD8+ T cells correlated with improved clinical outcome, raising the possibility that CD8+ T cells might play a pivotal role in anti-tumor immune response against MPMs. Thus stimulation of CD8+ lymphocytes might offer new opportunities for efficacious immunotherapy in MPM. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4784.

52 Dendritic cell-based immunotherapy for malignant pleural mesothelioma

52 Dendritic cell-based immunotherapy for malignant pleural mesothelioma